$value = 9.01e+21 + 0.01 - 9.01e+21;
print ( "first value is " , $value , "\n" ) ;
$value = 9.01e+21 - 9.01e+21 + 0.01;
print ("second value is " , $value, "\n" ) ;
$value = 9.01e+21 + 9.01e+21;
print ("thrid value is " , $value, "\n" ) ;
